According to The Local, specifics of the deal have not been announced yet, but according to Reuters, Russell Stover is the third largest candy company in the U.S. and has annual revenues of about $500 million. Russell Stover is known primarily for its boxed chocolates, but it also produces chocolates under the Whitman’s brand. Russell Stover products sell in more than 70,000 stores.

"This biggest and most important strategic acquisition to date in Lindt & Sprüngli's history is a unique opportunity for us to expand our North American chocolate business," said Lindt chief executive Ernst Tanner in a statement.

Lindt already has a presence in the U.S. with its own Lindt brand chocolates, and it also owns the Ghirardelli Chocolate Company.